
What Size Expansion Tank Do I Need?
When it comes to water heater expansion tanks, one size definitely does not fit all. Instead, the expansion tank size you need depends on your water heater capacity, your home’s water pressure level, and your plumbing system’s temperature rise. Most 40- to 50-gallon water heaters require a 2-gallon expansion tank, but pressure levels can change that. Why is this decision important? An undersized expansion tank can’t handle the volume of heated water that it should.







